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Study Finds Essential Differences Between Red and Giant Panda’s Skulls

Based on the latest study about the skulls of Red panda (Ailurus fulgens) and Giant panda (Ailuropoda melanoleuca), the research result is published in the recent edition of Biology Letters, explaining in detail the reason why these two mammals can coexist at the same time.

red and giant panda

Left: Red panda. Image credit: CC BY-SA 3.0 Right: Giant panda Bai Yun with a cub, Xiao Liwu, at the San Diego Zoo in December 2013. Image credit: San Diego Zoo.

According to Dr Z. Jack Tseng from the American Museum of Natural History, the study co-author, scientists have been engaged in identifying the differences between Red pandas and Giant pandas for quite a long period of time, because a basic principle in ecological science holds if two species of an organism utilize the same kind of resources for their lives, they are unable to co-exist under the same roof owing to the tough competition from each other.

This new research demonstrates how these two pandas co-exist, offering evidence that they eat different things from the study on the structure of their skulls.

Dr Tseng and his team, by application of high-resolution imaging and biting simulations, have found that the skulls of the two panda species are distantly related with structural differences in regard to how such animals chew their food.

These important differences clearly show the distinct bamboo feeding preferences of the pandas. Red pandas prefer the softer parts of the bamboo while Giant pandas like to eat the tougher stems of the plant.

As mammalian carnivores, the separation of Red pandas from Giant pandas has been evolved during the period of 40 million years.

Weighing nearly 4.5 kg, the Red panda has more close relationships with raccoons and weasels, but the Giant panda is much larger in size with weight about 100 kg and belong to the bear family Ursidae.

Geographically, the activity of both animals overlaps in the South China area, with their independent adaption to a diet incorporating mainly the same bamboo species.

Compared with the skull of the Giant panda, that of the Red panda is well-developed in distributing mechanical stress when it chews.

However the stronger skull of the Giant panda can bear greater and more concentrated forces and is easier to be damaged, when taking  the size differences between the these two animals into account.

Such differences demonstrate that in fact the species are able to process bamboo. A less-refined eater, the Giant panda are prone to chomping and swallowing.

Since the skull of the Giant panda is generally stronger and the peak biting stress is lower, it means that they are able to eat larger and harder pieces of bamboo.

With a weaker skull, the Red panda is better at distributing stresses, which enable it to chew longer and softer bamboo leaves more completely before they really swallow them.

Based on the information about the links between dietary preference and skull performance, it is possible to build up the foundation to illustrate why the Red panda and the Giant panda could co-exist for so long on this planet.

Journal Reference: 

Borja Figueirido et al. 2014. Three-dimensional computer simulations of feeding behaviour in red and giant pandas relate skull biomechanics with dietary niche partitioning. Biol. Lett., vol. 10, no. 4; doi: 10.1098/rsbl.2014.0196